1. Field of the Invention
This invention relates to a magnetic tape cartridge, and more particularly to a magnetic tape cartridge comprising a cartridge casing and a single reel around which a magnetic tape is wound and which is contained in the cartridge casing for rotation.
2. Description of the Related Art
There has been known a single reel magnetic tape cartridge, comprising a cartridge casing and a single reel around which a magnetic tape is wound and which is contained in the cartridge casing for rotation, as a recording medium for an external storage for a computer and the like. Such a single reel magnetic tape cartridge is used for retaining important data of a computer or the like and accordingly is arranged so that trouble such as tape jamming does not occur and the magnetic tape is not accidentally drawn out.
Further since various data are recorded on the magnetic tape, the magnetic tape cartridge is provided with a memory element so that the contents of the data recorded on the magnetic tape and the kind of the magnetic tape can be known without reading out the data from the tape. Such information on the contents of the magnetic tape is recorded on the memory element by a non-contact system such as electromagnetic induction and the information is read out from the memory element by a non-contact system.
The memory element is provided on the surface of the magnetic tape cartridge or inside the cartridge casing where the memory element does not interfere with rotation of the reel. It is required that the recording surface of the memory element is set at an angle required by the recording and reproducing system as the external storage or the like.
Further there has been known a single reel magnetic tape cartridge provided with a slide door for opening and closing a tape outlet opening, the slide door being urged toward the closing position by a spring. In such a single reel magnetic tape cartridge, there has been a problem that when the magnetic tape cartridge is loaded in the recording and reproducing system and the slide door is opened overcoming the force of the spring, counterforce of the urging force of the spring acts on the cartridge casing and rotates the magnetic tape cartridge in the recording and reproducing system. When the magnetic tape cartridge is rotated in the recording and reproducing system, the ejection mechanism of the recording and reproducing system cannot properly grip the magnetic tape cartridge and a corner portion of the magnetic tape cartridge can abut against the inner wall of the system when the magnetic tape cartridge is ejected from the recording and reproducing system, which can obstruct ejection of the magnetic tape cartridge.
In view of the foregoing observations and description, the primary object of the present invention is to provide a single reel magnetic tape cartridge on which the memory element can be mounted with its recording surface held at 45xc2x0 relative to the bottom surface of the cartridge casing as required by a recording and reproducing system.
Another object of the present invention is to provide a single reel magnetic tape cartridge in which the magnetic tape cartridge is prevented from being rotated in a recording and reproducing system.
The magnetic tape cartridge in accordance with a first aspect of the present invention comprises a cartridge casing formed by upper and lower casing halves mated together and a single reel around which a magnetic tape is wound and which is supported for rotation in the cartridge casing by the upper casing half, and is characterized by having a memory holder means which holds a non-contact type memory element with its recording surface held substantially at 45xc2x0 to the bottom surface of the cartridge casing.
It is preferred that the non-contact type memory element be square in shape in view of facility of mounting.
For example, the memory holder means may comprise a lower end face abutment portion which abuts against the lower end face of the memory element and an upper end face abutment portion which abuts against the upper end face of the memory element.
The terms xe2x80x9cthe lower end face of the memory elementxe2x80x9d and xe2x80x9cthe upper end face of the memory elementxe2x80x9d as used herein respectively mean the end face on the side of the lower casing half and the end face on the side of the upper casing half. The expression xe2x80x9cabuts against the end face of the memory elementxe2x80x9d means that the abutment portion abuts against the end face of the memory element and/or a portion of the upper or lower surface of the memory element near the end face.
For example, the lower end face abutment portion may be a recess which is formed in the lower casing half and snugly receives the lower end face of the memory element and the upper end face abutment portion may be a recess which is formed in the lower casing half at a portion where the lower casing half is butted against the upper casing half and snugly receives the upper end face of the memory element.
The memory holder means also may comprise a lower end face abutment portion which abuts against the lower end face of the memory element, an upper end face abutment portion which abuts against the upper end face of the memory element and an upper surface abutment portion which abuts against the upper surface of the memory element.
It is preferred that the lower and upper end face abutment portions abut against at least one of the side faces in addition to the respective end faces.
Further the memory holder means may comprise a lower side face abutment portion which snugly receives a part of the side faces of the memory element from below and an upper side face abutment portion which snugly receives a part of the side faces of the memory element from above.
Each of the upper end face abutment portion, the upper surface abutment portion and the upper and lower side face abutment portion may double as a reinforcement rib for reinforcing the upper or lower casing half.
It is preferred that the memory holder means be formed of a cushioning material and holds the memory element away from the inner surface of the cartridge casing. Otherwise a cushioning material may be disposed between the memory element and the memory holder means.
The cushioning material may be any material so long as it can cushion impact on the memory element, for instance, when the magnetic tape cartridge is dropped onto the floor. For example, elastic porous resin such as urethane foam, joint filler for tiling and the like may be employed.
Further it is preferred that the lower casing half be provided with a guide member which guides the memory element dropped toward the guide member to the position where the memory element is held by the memory holder means. The guide member may be, for instance, an inclined guide plate on which the memory element is slid to the position where the memory element is held by the memory holder means.
Since the non-contact type memory element is held substantially at 45xc2x0 to the bottom surface of the cartridge casing by the memory holder means, the magnetic tape cartridge of the first aspect of the present invention can satisfy requirement by a recording and reproducing system which requires that the recording surface of the memory element is at 45xc2x0 to the bottom surface of the cartridge casing.
Though the memory holder means may be of various structures, when the lower end face abutment portion is in the form of a recess which snugly receives the lower end face of the memory element, the memory element can be prevented from moving sideways and at the same time, positioning of the memory element upon incorporation of the memory element in the cartridge casing is facilitated.
Further when the upper end face abutment portion is in the form of a recess which is formed in the lower casing half at a portion where the lower casing half is butted against the upper casing half and snugly receives the upper end face of the memory element, the memory element can be held without forming an additional member, which simplifies the structure of the cartridge casing and facilitates manufacture of the cartridge casing.
Further when the memory holder means comprises an upper surface abutment portion which is formed on the upper casing half of the cartridge casing and abuts against the upper surface of the memory element in addition to the lower end face abutment portion which abuts against the lower end face of the memory element and the upper end face abutment portion which abuts against the upper end face of the memory element, the memory element can be surely held at 45xc2x0 to the bottom surface of the cartridge casing.
Further when the lower and upper end face abutment portions abut against at least one of the side faces in addition to the respective end faces, the memory element can be prevented from moving sideways and at the same time, positioning of the memory element upon incorporation of the memory element in the cartridge casing is facilitated.
Further when the upper end face abutment portion, the upper surface abutment portion and the upper and lower side face abutment portion double as reinforcement ribs for reinforcing the upper or lower casing half, the number of the components for holding the memory element can be reduced, which simplifies the structure of the cartridge casing and facilitates manufacture of the cartridge casing.
Further when the memory holder means is formed of a cushioning material and holds the memory element away from the inner surface of the cartridge casing, the memory element can be protected from impact applied to the cartridge casing from outside and prevented from being damaged by vibration of the casing or when the magnetic tape cartridge is dropped.
Further when the lower casing half is provided with a guide member which guides the memory element dropped toward the guide member to the position where the memory element is held by the memory holder means, the memory element can be held by the memory holder means at 45xc2x0 to the bottom surface of the cartridge casing by simply dropping the memory element with the casing held substantially horizontal, whereby positioning of the memory element upon incorporation of the memory element in the cartridge casing is facilitated.
Further the memory holder means may comprise a through hole formed in a non-recording area of the memory element and a post-like projection which is formed in the cartridge casing and is fitted in the through hole to hold the memory element with its recording surface inclined at 45xc2x0 to the bottom surface of the cartridge casing.
For example, the through hole is formed so that at least a part of the inner peripheral surface of the through hole is inclined at about 45xc2x0 to the recording surface of the memory element and the post-like projection is formed so that at least a part of its outer surface extends vertical to the bottom surface of the cartridge casing, and the post-like projection is fitted into the through hole so that the inclined part of the inner peripheral surface of the through hole is brought into contact with the vertical part of the outer surface of the post-like projection.
When the diameter of the post-like projection is such that the post-like projection is press-fitted in the through hole, the memory element can be firmly held by the post-like projection.
Further the post-like projection may be provided with a support shoulder which is brought into contact with the surface of the memory element to hold the memory element at 45xc2x0 to the bottom surface of the cartridge casing. Also at this time, it is preferred that the diameter of the post-like projection be such that the post-like projection is press-fitted in the through hole so that the memory element can be firmly held by the post-like projection.
In accordance with a second aspect of the present invention, there is provided a magnetic tape cartridge to be loaded in a recording and reproducing system comprising a cartridge casing which is substantially rectangular in shape, a single reel around which a magnetic tape is wound and which is supported for rotation in the cartridge casing and a door which opens and closes a tape outlet opening which is formed in a side wall of the cartridge casing and through which the magnetic tape is drawn out of the cartridge casing, the door being movable along the side wall between an opening position and a closing position and urged toward the closing position by an urging means, wherein the improvement comprises that an engagement recess is formed in a side wall of the cartridge casing to be brought into engagement with a stopper member in the recording and reproducing system when the magnetic tape cartridge is loaded therein, thereby preventing the magnetic tape cartridge from being rotated under turning moment which is generated by counterforce against the force of the urging means when the door is moved to the opening position overcoming the force of the urging means.
It is preferred that the engagement recess conforms to the stopper member in shape and is arranged to be applied from the stopper member with load which cancels said turning moment.
Further it is preferred that the engagement recess be provided with a surface which is faced upward and receives force directed toward the bottom surface of the cartridge casing when the engagement recess is engaged with the stopper member.